1. Field of the Invention:
The present invention relates to a magnetic recording medium which is prepared by forming a magnetic layer on a substrate by coating a magnetic powder composition comprising a magnetic powder and a binder as main components.
2. Description of the Prior Art:
In general, it has been known that a kind of a binder used for bonding a magnetic powder on a substrate in such magnetic recording media highly affects to an electromagnetic transfer characteristic and physical characteristics such as repeat running durability and adhesive strength.
Heretofore, two component type binders comprising two kinds of resins such as urethane type resins, vinyl chloride-vinyl acetate type resins, cellulose type resins, phenoxy type resins, epoxy type resins and ester type resins have been mainly used as the binder. The combinations of polyurethane and nitrocellulose or the combinations of polyurethane and vinyl chloride-vinyl acetate copolymer have been mainly employed. However, the two component type binders have not attained satisfactory electromagnetic transfer characteristic and physical characteristics such as repeat running durability and adhesive strength. Even though the ratio of the two components is varied, the tendency of the electromagnetic transfer characteristic is inconsistent with that of the physical characteristics. It has been difficult to obtain a magnetic recording medium having satisfactory characteristics.